Paradigm shift in treatment of Proliferative Diabetic Retinopathy.

Diabetic retinopathy is a leading cause of vision loss in the United States. If you have not read much on diabetic retinopathy, I suggest reading our diabetic retinopathy pamphlet and also visit the American Academy of Ophthalmology website first for background information.

Proliferative diabetic retinopathy or PDR is the most severe stage of diabetic retinopathy.  At this stage, patients are at high risk of severe vision loss.  Severe vision loss can be caused by vitreous hemorrhage, diabetic macular edema (DME), severe ischemia and tractional retinal detachment (TRD).

The standard of care for PDR has been pan-retinal photocoagulation (PRP). Timely treatment reduces the risk of vitreous hemorrhage and retinal detachments.  However, PRP does have some side effects.  Patient with DME may experience worsened DME as the result of PRP laser, patients may experience worsened night vision and peripheral vision.  Recent changes in PRP treatment parameters may lessen these side effects, but they still may be a problem for some patients.

In late 2015, the Diabetic Retinopathy Clinical Research Network (DRCRNet) completed Protocol S.  Protocol S compares the traditional treatment of Proliferative Diabetic Retinopathy (PDR) using PRP laser with monthly injections of Lucentis.

The full study publication can be read at the DRCRNet website.  The conclusion of the study shows that monthly injections of Lucentis in patients with PDR can achieve comparable results to PRP laser for the treatment of PDR.  In addition, patients who received Lucentis treatment have a lower incidence of vitreous hemorrhage, have less DME, and less peripheral vision loss. This group also experience slightly better visual acuity outcome compared to the group that received PRP laser treatment.

Should you opt for monthly Lucentis injections rather than PRP laser if you have PDR?  This is worth a discussion with your retina specialist.  Important factors of concern are the specifics of your disease.  Not all patients with PDR have the same severity and characteristics. The presence of absence of DME and the degree of proliferative membranes for example.

Patients should also consider how feasible it is for them to come in for monthly injections.  Although most patients only need monthly injections at first, and less frequently as their disease stabilizes, they still likely would need more office visits than those receiving PRP laser.

Cost is an important factor.  Each Lucentis 0.5mg dose is about $1800.  A patient with PDR in both eyes will need 2 doses every month at first.  This does not include your doctor’s fees.  The cost may be mitigated to some degree by using Avastin (~ $65 per dose) injections in place of Lucentis.  Protocol S did not look at the efficacy of Avastin injection for PDR.  However, DRCR Protocol T did compare Lucentis and Avastin for treatment of DME.  The results are published here.  These results indicate that Avastin and Lucentis have similar outcomes for treatment of DME.  Does this mean Avastin and Lucentis will have similar outcomes for treatment of PDR?  We don’t’ have enough data to answer this question at this time.  Talk to your retina specialist for his/her opinion.

Other factors to consider:  Injections are surprisingly painless but do carry a low risk of infection and other complications. And lastly, the Protocol S only published data for 2 years.  We don’t know how each group compares beyond the 2 years.

Keep in mind that these treatments are not mutually exclusive.  It’s not uncommon for patients to receive both PRP laser and Lucentis injections.